This is an initial submission in response to PAR-07-024 (originally PAR-06-216) titled "Ancillary Studies to Obesity-Related Clinical Trials." This application is designed to serve as an ancillary study to the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS;U01 DK072493;PI: Thomas Inge, M.D.) consortium. Teen-LABS is a four-center consortium working in cooperation with NIH scientific staff to conduct coordinated clinical research in adolescents who undergo bariatric surgery. This ancillary study, approved by the Teen-LABS Ancillary Study Committee, proposes to investigate changes in dietary intake and eating behavior in 110 Teen-LABS participants and compare them with responses in 110 obese adolescents treated with a lifestyle modification program. As America's obesity problem continues to grow, there is a need for additional research on the effectiveness of innovative treatments. Bariatric surgery for adults with extreme obesity has exploded in popularity over the past decade. The sizable weight losses seen with bariatric surgery are well maintained and accompanied by improvement, if not resolution, of several obesity-related comorbidities and psychosocial status. Postoperative changes in dietary intake and eating behavior, which are thought to play a critical role in postoperative outcomes, have received less attention. The dietary and eating behavior outcomes of bariatric surgery in adolescents are virtually unknown. These issues may be particularly important because of adolescents'developmental status at the time of surgery as well as their longer life expectancy. The main trial of the Teen-LABS consortium will not specifically study changes in dietary intake and eating behavior before and after bariatric surgery. We propose to study postoperative changes in these areas in a subset of 110 adolescents who undergo bariatric surgery in Teen-LABS. We predict that these adolescents will report significant improvements in their dietary intake (including reduced total calories per day and decreases in percentage of calories from sugar) at 6, 12, and 24 months postoperatively as compared to obese adolescents treated with a lifestyle modification program. We also anticipate that adolescents who undergo bariatric surgery will report greater improvements in eating behavior (including less frequent binge eating, higher levels of dietary restraint, as well as lower levels of disinhibition and hunger) as compared to obese adolescents treated in the lifestyle modification program. The Teen-LABS consortium provides an ideal opportunity to complete this innovative ancillary study in a large and diverse sample of adolescents who undergo bariatric surgery. PUBLIC HEALTH RELEVANCE: In the proposed ancillary study to the Teen-LABS consortium, we plan to investigate changes in dietary intake and eating behavior in adolescents who undergo bariatric surgery.